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February 1, 2005
UNPROTECTED PEOPLE #72: INFANT DIES AFTER CONTRACTING PERTUSSIS FROM ADULT
FAMILY MEMBERS

The Immunization Action Coalition (IAC) publishes articles about people who
have suffered or died from vaccine-preventable diseases and periodically
devotes an IAC Express issue to such an article. This is the 72nd in our
series.

In December 2004, a 29-day-old infant died from pneumonia and respiratory
failure, complications of pertussis. Several weeks before the infant's
birth, her mother and maternal grandmother had developed prolonged
paroxysmal cough with posttussive vomiting.

According to information published in MMWR on January 28, 2005, during
1996-2004, 35.1% of pertussis patients were 6 months of age or younger (http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5403a3.htm).
Infants this age are particularly vulnerable to the disease because they are
too young to have received the 3-dose primary series of pertussis vaccine.

CDC describes pertussis as a highly communicable disease, transmitted from
patients to close contacts by respiratory droplets. It can be severe in
nonimmunized infants; healthcare workers should suspect pertussis in
nonimmunized or partially immunized infants with respiratory distress.

The following case report is based on information from a medical school,
hospital, and local and state public health agencies in West Virginia, as
well as from NIP staff. Titled "Brief Report: Fatal Case of Pertussis in an
Infant--West Virginia, 2004," it appeared in MMWR on January 28, 2005.

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In December 2004, an infant aged 29 days in West Virginia died from
pertussis after exposure to adult family members with probable undiagnosed
pertussis. Pertussis (i.e., whooping cough) is a prolonged respiratory
illness caused by the bacterium Bordetella pertussis and characterized by a
violent cough, inspiratory whoop, and posttussive vomiting. The cough often
lasts from several weeks to up to 3 months. However, adolescents and adults,
even those previously vaccinated as children, often have disease not
recognized as pertussis, leading to intrafamilial and nosocomial
transmission. In the United States, children aged <6 months are at the
highest risk for severe illness or death from pertussis because most infants
do not complete their primary vaccination series until age 6 months. This
report summarizes results of the West Virginia Department of Health and
Human Resources (WVDHHR) case investigation, which underscore the critical
need to prevent pertussis transmission to infants from adolescents and
adults with undiagnosed disease.

On December 11, the infant was taken by her parents to a local emergency
department (ED) with difficulty breathing. The infant had been coughing for
approximately 5 days with increasing severity, resulting in posttussive
vomiting and several choking episodes. At presentation, the infant was
lethargic, and examination revealed tachycardia and mild fever (99.5 degrees
F [37.5 degrees C]). Before intubation and oxygen supplementation, the
infant had thick, foamy mucus coming from her mouth, appeared cyanotic, and
had an O2 saturation of 70% by pulse oximetry. Seizure activity was noted
during intubation. Laboratory results revealed severe leukocytosis (white
blood cell count: 104,100/microliter; normal: 5,000-19,500 microliter),
severe lymphocytosis (26,600/microliter; normal: 2,500-16,500/microliter),
and a nasopharyngeal swab was positive for respiratory syncytial virus (RSV)
by rapid immunoassay alone. A chest radiograph revealed right upper lobe and
perihilar infiltrates, and an electrocardiogram indicated supraventricular
tachycardia. Three hours after arrival at the ED, the infant was transferred
to a pediatric intensive care unit (PICU) with diagnoses of pneumonia and
respiratory failure.

On transfer to the PICU, the infant was placed on droplet precautions and
contact isolation, treated for suspected sepsis, and started on azithromycin
for presumed B. pertussis infection on the basis of clinical signs. The
infant's ventilator course was characterized by hypoxemia (admission
PaO2/FiO2 ratio: 172) and increasing hypercarbia. Sequential cardiac
ultrasounds demonstrated increasing pulmonary hypertension (right
ventricular pressure: 2/3 systemic). Nineteen hours after admission,
oxygenation worsened precipitously (PaO2/FiO2 ratio: 52-60) and failed to
improve with nitric oxide administration or high-frequency ventilation. A
double-volume exchange transfusion was performed, but the infant failed to
improve and died approximately 30 hours after admission to the PICU.

A specimen obtained from the infant's nasopharynx after admission to the
PICU was reported at the time of the infant's death to be positive for B.
pertussis DNA and negative for B. parapertussis DNA by polymerase chain
reaction (PCR); however, no specimen was submitted for culture. Results were
negative by both rapid immunoassay and culture for RSV, influenza A and B,
and parainfluenza viruses 1, 2, and 3, and negative by culture for
adenovirus. The diagnosis of confirmed pertussis was based on history,
clinical findings, and a positive PCR test. The infant might have had a
coinfection with RSV based on the positive RSV rapid immunoassay at the ED;
this result was not confirmed by a repeat RSV rapid immunoassay or by
culture at the PICU.

The infant was born at 36 weeks' gestation (birth weight: 2,665 g) by
normal, uncomplicated, vaginal delivery. The infant's mother, aged 20 years,
had a prolonged paroxysmal cough with posttussive vomiting and whoop that
began approximately 3 weeks before the infant's delivery. The cough was
still present at the time of the infant's death. The mother received
guaifenesin/dextromethorphan cough syrup after delivery. The infant's
maternal grandmother, aged 58 years, had a prolonged paroxysmal cough
illness (onset date: approximately 2 weeks before the infant's mother's
illness) with posttussive vomiting; she had received azithromycin after a
diagnosis of sinusitis. Two weeks before the infant's illness, the infant's
father, aged 22 years, had onset of a paroxysmal cough illness of >3 weeks'
duration.

A day after the infant's death, a case investigation identified four
additional close contacts (two cousins, a paternal grandmother, and a
great-grandmother) of the infant with cough illness (duration: 3-8 days) at
the time of the infant's death. The birth hospital and the ED had no droplet
precautions in place while the infant and the infant's symptomatic family
members were in the facilities; 30 birth hospital and 11 ED employees were
identified as potential contacts. The local health department and the ED
provided erythromycin to 24 recent (i.e., during the preceding 3 weeks)
contacts of the infant and symptomatic family members. Of nine
nasopharyngeal swabs submitted for culture, all were negative for pertussis
(all household members swabbed had been symptomatic for >3 weeks); no PCR
testing for pertussis was performed. Pertussis alerts were issued to the
public, healthcare providers, schools, and a large retail store where the
infant's father worked.

This case underscores the need to protect infants from pertussis
transmission. The healthcare community can limit the spread of pertussis by
(1) educating caretakers and the public about preventing exposure of infants
to any person with a cough illness, (2) educating healthcare providers to
consider pertussis in adolescents and adults with a cough illness and to ask
these patients to wear a mask or isolate themselves from other patients, and
(3) encouraging confirmation of pertussis by culture of nasopharyngeal
secretions. Healthcare providers must be encouraged to observe droplet
precautions while attending to patients with respiratory illnesses. No
U.S.-licensed pertussis vaccine for persons aged >=7 years is available;
however, in 2004, two pharmaceutical companies submitted biologics license
applications to the Food and Drug Administration for two tetanus toxoid and
reduced diphtheria toxoid and acellular pertussis vaccine adsorbed (Tdap)
products, one for persons aged 10-18 years and the other for persons aged
11-64 years.

DISCLAIMER: The Immunization Action Coalition (IAC) publishes Unprotected
People reports for the purpose of making them available for our readers'
review. We have not verified this report's content, for which the authors
are solely responsible.

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